Method of making anhydrous magnesium chloride



Patented Sept. 6, 1932 UNITED STATES KARL STAIB, 0F .BITTERFELD, GERMANY,

ASSIGNOR', "BY MESNE ASSIGNMENTS, T0

MAGNESIUM DEVELOPMENT CORPOBATIOI Q',A CORPORATION OF DELAWARE METHOD or MAKING annxnnous MAGNESIUMCHLORIDE' No Drawing. Application filed March 6, 192a, Serial-N0. 259,595, at inGermany March e, 1926. A

This invention relates to the production of molten anhydrous magnesium chloride from magnesium oxide.

This application is a continuation in part of my copending application Serial No. 17 2,- 216, filed March 2, 1927.

In maintaining reactions between solids and gases, especially at elevated temperatures, it is often diflicult to provide the solid substance with a surface suificiently large to maintain the reaction at the desired velocity, without provoking, where the reaction is exothermic, a detrimental sintering or melting. Consequently it is necessary to either continuously expose fresh surfaces to the reactant gas by agitating or stirring the pulverized solid substances or to mix the finely purverized solid substances with pore-forming materials and to then convert the mixture into solid form.

It has been attempted to avoid these difficulties by applying the principles of coaldust firing to the exothermic oxidation of substances which are easily oxidized by air, for instance, sulfides, or to the nitrogenization of carbides. A similar process has also been recommended for the production of metal halides, particularly aluminum chloride in volatile form, from raw material con taining the corresponding metal oxide, by injecting such pulverized raw material, together with fuel, a combustion-supporting gas such as air, and a halogen, into a combustion and reaction chamber. However, the presence of air in the reaction mixture causes partial decomposition of the halide formed and thus, although rendering the process thermally self-supporting, tends to diminish the amount of product obtained.

Another process of making volatile aluminum chloride provides for the introduction of aluminous material, fuel (carbon) and chlorine without a combustion-supporting gas into a combustion and reaction chamber. In this case, however, it is necessary'to apply external heat throughout the entire course of reaction.

The present invention is concerned with the production of molten anhydrous magnesium chloride from magnesium oxide or magnesium oxide-bearing materials, and it has as a principal object the avoidance of the difficulties of such former processes, that is to say, the avoidance of the necessity of introducing, with the-reaction mixture proper,

suspended in a current of chlorine and are injected thusly; into a reaction chamber whichhas been sufficiently preheated to initiate the reaction. For this latter purpose the reaction chamber is preferably preheated to the reaction temperature by any c0nvenientheating device. This initial preheating once accomplished, additional heating may be dispensedwith, the heat of reaction sufiicing to maintain a proper reactionv temperature. In order that the invention may be fully understood the following examples will be ref r d Eagample A mixture of finely ground magnesium oxide and finely ground carbonaceous material, as charcoal or cokified peat in the proportion .of about a parts of MgO and 1 part of charcoal injected by means of a current of chlorine through a nozzle into a chamber preheated to 700 C. The temperature of the reaction chamber is then maintained by the reaction heat and the supplementary heating may be discontinued. The" small drops of the resulting anhydrous magnesium chloride collect so that the molten mass can be withdrawn from the bottom of the reaction chamber and filtered, if necessary, from the excess of carbon.

The ratio of components may be, as a rule, between one and two atoms of carbon to two molecules of magnesium oxide. vAs the resulting reaction temperature depends not only upon the exothermicformation of carbon monoxide or dioxide, but also upon the dimensions of the apparatus employed, the mixture when carrying out the process on an industrial scale, is to be proportioned in such a manner that a minimum excess of coal is left in the molten final product. However, an undesired excess of coal may also ulti mately be removed from the melt, for instance by filtering.

I claim V 1. The process of converting magnesium oxide into anhydrous molten magnesium chloride comprising introducing a mixture of about 4 parts of finely ground magnesium 1O oxide and about one part of finely ground cokefied peat, suspended in a current of chlo- V rine gas into a reaction chamber preheated to about 700 C.,.the.rea ction heat 'suflicing to maintain the reaction temperature, and

[5 withdrawing molten magnesium chloride from said reaction chamber. 1

E2. The process of converting magnesium oxide into anhydrous molten magnesium chloride comprising introducing a mixture of finely ground magnesium oxide and finely ground carbonaceous material SuSpended in a current offchl'orine gas, into a" reaction chamber sufiiciently preheated to start, the

reaction, and Withdrawing molten chloride 'from salid chamber, the heat of reaction sufficing to maintain the reaction."

3. The process of converting magnesium oxide into anhydrous molten magnesium chloride comprising introducing a mixture of finely ground magnesiumfoxide and carbonaceous materiahsuspended in' a current of chlorine gas, into a reaction chamber pre-- heated to about 700 centigrade, thetreaction heat sufiicing to maintain the'reaction temperature, and withdrawing molten mag v1 nesium chloride from said reaction chamber.

4. Theprocess which comprises introducing a mixture of finely divided magnesium oxide and finely ground cokefied peat in a 4 current of chlorine gas into a reaction chamber .sufficiently preheated-to start the reaction, and'withdra'wing molten chloride from said chamber, the heat of reaction sufiicing to maintain the reaction. In testimony whereof I aflixvm y signature.

' KARL STATE. 

